Tube cutting tool

ABSTRACT

A cutting tool is lowered into a well bore over a string of tubes to cut the tubing at any desired depth by rotation of the tool body. Spring blades anchored to the tool body at their lower ends, project through openings into the body and mount cutting tips at the upper ends engageable with the tubing.

United States Patent 1530,6316 1 3/1925 Anderson et a] l66/55.6 1,535,348 4/1925 Segelhorst 166/556 1,625,393 4/1927 Reilly et al 166/556 Primary Examiner-David H. Brown Att0rneys- Clarence A. O'Brien and Harvey B. Jacobson ABSTRACT: A cutting tool is lowered into a well bore over a string of tubes to cut the tubing at any desired depth by rotation of the tool body. Spring blades anchored to the tool body at their lower ends, project through openings into the body and mount cutting tips at the upper ends engageable with the tubing.

TUBE CUTTING TOOL This invention relates to well recovery operations and more particularly to the cutting of tubing at a desired depth within a bore hole.

During subterranean recovery operations, the tubing installed in a completed well becomes stuck or packers fail to release so that the tubing must be cut in order to retrieve the upper portion. Toward this end, a tool is lowered into the well bore over the tubing for among other purposes to cut it at the desired location. Such cutting tools are however relatively limited in use because of dimensional restrictions. It is therefore an important object of the present invention to provide a tool that is exclusively useful as a pipe cutter and may accommodate well bores and tubing of varying dimensions to effectively cut a tube string.

In accordance with the present invention, the pipe cutting tool includes an elongated tubular body, having a relatively thin wall of sufficient strength to resist torsional stress applied. Spring blades are anchored to the tubular body at the lower ends so that the upper ends of the blades may be elastically deflected outwardly through openings formed in the tubular body for this purpose. Cutting tips are mounted at the upper ends of the spring blades for engagement with the tubing. As the tool body is inserted downwardly into the well bore, the spring blades will be deflected outwardly through the openings by obstructions on the tubing such as upsets, centralizers, valves, etc. In the undeformed state of the spring blades, the cutting tips contact each other. Accordingly, when the tool body is positioned about the tubing, the cutting tips will engage the tubing with sufficient force so that rotation of the tool body will effectively cut the tubing at the desired location.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIG. 1 is a perspective view of the cutting tool.

FIG. 2 is an enlarged longitudinal sectional view taken substantially through a plane indicated by section line 2-2 in FIG. I.

FIG. 3 is a longitudinal sectional view of the cutting tool in use.

FIG. 4 is a transverse sectional view taken substantially through a plane indicated by section line 4-4 in FIG. 3.

slots. It willbc apparent, that the slots and recesses in the tubular body make it unsuitable for transmission of high axial forces. Further, the wall thickness of the tubular body 12 is as narrow as possible consistent with a torsional. stress capability necessary to transmit torque to a plurality of spring blades 34.

Each of the elongated slots 28 is associated with one of the spring blades 34. Each spring blade includes a lower anchor end portion 36 slidably fitted within a dovetailed recess 32. The anchor end portion is provided with an aperture 38 aligned with a threaded aperture 40 formed in the tubular body for receiving a screw fastener 42. The spring blade is thereby securely anchored externally to the tubular body 12 and projects upwardly and radially inwardly into the tubular body through the slot 28. Accordingly, the spring blade has a curvature in its undeformed state characterized by a radius of curvature that decreases in an upward direction toward an upper cutting end 44 of the blade. The upper ends of the blades mount tungsten carbide cutting tips 46 that contact each other along the longitudinal axis of the tubular body 12 in the undeformed state of the spring blades as shown in FIG. 2.

It will be apparent that during downward movement of the cutting tool 10 over the tubing 26, the spring blades will be elastically deflected outwardly of the longitudinal axis of the body I2 by engagement with the external surface ofthe tubing as shown in FIG. 3. It will furthermore be appreciated that the FIG. 5 is an enlarged partial sectional view taken substantially through a plane indicated by section line 5-5 in FIG. 2.

Referring now to the drawings in detail, the cutting tool generally denoted by reference numeral 10, is shown in FIGS. 1' and 2 prior to being used. In this condition, the cutting tool includes an elongated tubular bodyv 12 having a lower end 14 internally threaded so as to be threadedly connected to a tubular guide shoe [6. The upper end 18 of the tool body is also internally threaded for threaded reception of a torque transmitting tube. In FIGS. I and 2 however, the upper threaded end 18 of the tool body is closed by a threaded protector cap As shown in FIG. 3, upon removal of the protector cap 20, the upper end 18 of the tool body is threadedly connected to the lower end of a torque transmitting tube 22 by means of g which the tool is lowered into a well bore or well casing 24 about 'a string of tubes 26 for cutting the tubing at any desired depth. The guide shoe 16 is therefore designed to facilitate downward movement of the tool body through the well bore.

The tubular body is provided with a plurality of circumferentially spaced slots or openings 28 that are equally spaced from each other. In the illustrated embodiment, there are four slots 28 which extend parallel to the longitudinal axis of the tubular body 12 in equal spaced relationship to each other. The upper ends 30 of the slots are beveled outwardly while the lower ends of the slots terminate at external, dovetailed recesses 32 that extend in longitudinal alignment with the spring blades may move radially outwardly through the slots 28 at the upper ends in order to accommodate diametrical enlargements or obstructions on the, tubing such as upsets, centralizcrs, valves, etc. When the cutting tool has reached a desired depth, the body 12 may be rotated so that the cutting tips 46 in engagement with the tubing will cut it at the desired location.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What I claim as new is as follows:

I. A cutting tool for tubing within a well bore comprising a tubular body adapted to be inserted into the well bore in surrounding relation to the tubing, said tubular body having a lower end and an upper end, a plurality of spring blades having lower end portions anchored externally to the tubular body and upper end portions projecting through openings into the tubular body, cutting tips secured to the upper portions of the blades, said blades being elastically displaceable from undeformed positions with the cutting tips in contact with each other toward deformed positions with the upper end portions projecting into said openings.

2. The combination of claim I wherein each of said spring blades has a curvature in the undeformed state thereof of decreasing radius in an upward direction longitudinally of the tubular body.

3. The combination of claim 2 including a guide shoe connected to the lower end of the tubular body.

4. The combination of claim I wherein each of said openings in the tubular body is formed by a longitudinally elongated slot having one end in communication with an external recess in the body receiving the lower end portion of one of the spring blades, and anchoring means fixedly securing the blades to the body within the external recesses.

5. The combination of claim 4 wherein each of said spring blades has a curvature in the undeformed state thereof of decreasing radius in an upward direction longitudinally of the tubular body.

6. The combination of claim 5 including a guide shoe connected to the lower end of the tubular body.

7. A cutting tool comprising a tubular body dimensioned for torsional loading only having a plurality of elongated openings formed therein, a plurality of flexible blades having anchor ing the blades externally on the body in close spaced relation to the openings.

10. The combination of claim 9 wherein said blades have curvatures in the undeformed state decreasing in radius in a direction from the anchor ends to the cutting ends. 

1. A cutting tool for tubing within a well bore comprising a tubular body adapted to be inserted into the well bore in surrounding relation to the tubing, said tubular body having a lower end and an upper end, a plurality of spring blades having lower end portions anchored externally to the tubular body and upper end portions projecting through openings into the tubular body, cutting tips secured to the upper portions of the blades, said blades being elastically displaceable from undeformed positions with the cutting tips in contact with each other toward deformed positions with the upper end portions projecting into said openings.
 2. The combination of claim 1 wherein each of said spriNg blades has a curvature in the undeformed state thereof of decreasing radius in an upward direction longitudinally of the tubular body.
 3. The combination of claim 2 including a guide shoe connected to the lower end of the tubular body.
 4. The combination of claim 1 wherein each of said openings in the tubular body is formed by a longitudinally elongated slot having one end in communication with an external recess in the body receiving the lower end portion of one of the spring blades, and anchoring means fixedly securing the blades to the body within the external recesses.
 5. The combination of claim 4 wherein each of said spring blades has a curvature in the undeformed state thereof of decreasing radius in an upward direction longitudinally of the tubular body.
 6. The combination of claim 5 including a guide shoe connected to the lower end of the tubular body.
 7. A cutting tool comprising a tubular body dimensioned for torsional loading only having a plurality of elongated openings formed therein, a plurality of flexible blades having anchor ends secured to the body and cutting ends deflectable outwardly of the body through said openings, and cutting tips secured to the blades at said cutting ends.
 8. The combination of claim 7 wherein said blades have curvatures in the undeformed state decreasing in radius in a direction from the anchor ends to the cutting ends.
 9. The combination of claim 7 including means for anchoring the blades externally on the body in close spaced relation to the openings.
 10. The combination of claim 9 wherein said blades have curvatures in the undeformed state decreasing in radius in a direction from the anchor ends to the cutting ends. 